Laski, Harold J.
George Allen and Unwin, 1955
Buku Teks
Laski, Harold J.
George Allen and Unwin, 1957
Buku Teks
Healy, Phyllis M.
The Institute of Nationale Language and The Summer Institute Linguistics, 1960
Buku Teks
Crocker, Mary E. Coffman
McGraw-Hill, 1990
Buku Teks
Jespersen, Otto
George Allen and Unwin, 1933
Buku Teks